A convenient synthesis of N-tert-butyloxycarbonyl-O-benzyl-L-serine.
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Biomedical subjects
Publications and source records attributed to H Sugano.
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A clinico-pathological study of 20 cases of mixed mesodermal tumor of the uterine body is reported. Fifteen tumors were found after menopause. The mean age of all cases was 55.5 years. Histologically, mixed mesodermal tumors consisted of two different components; epithelial and sarcomatous patterns, in 18 cases. Mixed mesodermal tumors in four of the 18 cases had no adenocarcinomatous elements but showed a benign glandular structure. In the remaining two tumors, epithelial patterns were absent and only heterologous sarcomatous elements were found. Ten of the patients had received hysterectomy more than five years ago. Three of these patients, having no malignant but benign epithelial component, showed a relatively good prognosis. Adenocarcinomatous elements were found in six cases, and four patients with carcinomatous elements had poor prognosis. It can be stated that the prognosis of mixed mesodermal tumor chiefly depends on the malignancy of epithelial components, when comparing the prognosis of the tumors at the same clinical stage. On the other hand, sarcomatous elements are not likely to reflect the prognosis of the tumors. Mixed mesodermal tumor is monodermal in origin, namely, mesodermal origin, and might arise from the Muellerian duct or more primitive mesodermal tissue.
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The 220-MHz proton magnetic resonance spectrum of the cyclic decapeptide antibiotic, mono-N-methylleucine gramicidin S, is reported and all the resonances have been assigned to specific protons of the constituent amino acids. Three methods--temperature dependence and solvent mixture (methanol-trifluoroethanol and dimethyl sulfoxide-trifluoroethanol) dependence of peptide NH proton chemical shifts and proton deuteron exchange--habe been utilized to delineate peptide NH protons. The results of the above methods, coupled with the observed vicinal alpha-CH-NH coupling constants and chemical shifts, indicate that in trifluoroethanol the peptide NH PROTONS OF D-Phe4, D-Phe9, L-Orn2, and L-Val6 are exposed to the sovent, and those of L-Val1, L-Orn7, and L-Leu8 are solvent shielded and intramolecularly hydrogen bonded. In trifluoroethanol, dimethyl sulfoxide, and methanol, the decapeptide has no C2 symmetry, and there are only minor conformational differences in the different solvents. In the proposed conformation in trifluoroethanol, one-half of the decapeptide retained the hydrogen bonding pattern of gramicidin S, i.e. cyclo-(L-Val1 NH--O-C L-Leu8) (a beta turn) and cyclo-(L-Leu8 NH--O-C L-Val1). The second half of the molecule exhibits a different type of stable beta turn involving the ten-atom hydrogen-bonded ring, cyclo-(L-Orn7-NH--O-C D-PHE4).
A long-term cultured Friend leukemia cell is able to differentiate along the erythrocytic series following treatment with some substances and that can be demonstrated by a conjugated erythrocyte membrane-specific antibody technique. Differentiation is induced by inhibition of DNA synthesis and by dimethylsulfoxide (DMSO), erythropoietin (EP) and Vitamin B12 (B12), and other agents. The effective substances were divided into 2 groups by the mode of differentiation of Friend cells. A differentiated state continues for several days when cells are re-cultured in the medium without substances. The decreased tumorigenecity of differentiated cells is proved by back transplantation to mice.
From 1968 to 1973, 793 cases of nasopharyngeal malignancies in Japan were examined histopathologically and immunologically. The majority of the carcinomas were undifferentiated squamous cell carcinomas, including transitional cell carcinoma and lymphoepithelioma. These findings correspond well with those of other countries. There were more well differentiated carcinomas in the old than in the young age groups. The positive rate (80%) and the geometric mean of the anti-VCA-antibody titers (more than 1:750) were remarkably high in the lymphoepithelioma group. These two factors seem to be very important to the study of oncogenesis of nasopharyngeal carcinoma (NPC). The relationship between subpopulations of peripheral lymphocytes in NPC and histopathological classification was investigated. The lymphoepithelioma group had a higher proportion of B cells (complement receptor cells) to T cells (erythrocyte rosette forming cells) than healthy persons throughout the clinical course, and its prognosis was not good.
The effect of 4-isopropylcatechol (4-IPC), a potent, irreversible cutaneous depigmenting agent, on protein biosynthesis of malignant melanoma cells in mice was studied by examining the in vitro amino acid (leucine) incorporation into a microsome fraction in cell sap. The present study revealed that 4-IPC does not inhibit the protein biosynthesis of the cell-free system in mouse liver, but remarkably inhibits it in mouse melanoma cells, which contain a high level of tyrosinase. The enhanced inhibition was found also in the mouse liver cell-free system when tyrosinase was added. Air oxidation products of 4-IPC were not responsible for such inhibition. These results may indicate that 4-IPC directly inhibits protein biosynthesis, probably by some intermediates that occur in an early stage of enzymatic oxidation of 4-IPC.
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